Each year NDSU picks a tough-to-control weed to highlight as the weed of the year in the ND Weed Control Guide. This year the weed of the year is green foxtail. Green foxtail is sometimes referred locally as pigeongrass.
Green foxtail is a warm-season annual grass that thrives both in tilled and no-till cropping practices and can be commonly found in several different growing conditions from roadsides, disturbed sites in pastures turf grass and cropland. It is a heavy seed producer, with an average of 34,000 seeds per plant. Seeds can remain viable in the soil for about three years. Effort is needed to reduce seed reserves in the soil as only a few surviving plants are sufficient to replenish the seedbank.
In small grains and in broadleaf crops such as sunflower, pulse crops, flax and others, green foxtail control is highly dependent on the use of Group 1 (ACCase) herbicides such as clethodim (Select), quizalofop (Assure II), pinoxaden (Axial), fenoxaprop (Puma) or clodinafop (Discover). However, repeated use of these herbicides with the same mode of action has led to the development of herbicide-resistant populations. There have also been reported cases of resistance to Group 2 (ALS) herbicides such as flucarbazone (Everest), pyroxsulam (Goldsky) and thiencarbazone (Huskie Complete, Varro).
Growers should consider utilizing soil-applied herbicides and more diverse crop rotations to reduce the impact of green foxtail. Herbicides such as Sonalan (ethalfluralin), Dual (metolachlor), Outlook (dimethenamid), Harness (acetochlor) and Zidua (pyroxasulfone) will provide a different mode of action to control green foxtail. Including a Roundup or Liberty tolerant crop in the crop rotation is another option for including a different herbicide mode of action to control green foxtail.
More information can be found in the 2021 ND Weed Control Guide on page 134. Copies of the 2021 Weed Control guide can be picked up at the Extension office or found online at www.ag.ndsu.edu/weeds. For more information, contact Alicia Harstad at the Stutsman County Extension office at firstname.lastname@example.org or 701-252-9030.